1. Field of the Invention
This invention relates to door controls and in particular to doors employing push rails or pads which monitor attempts to egress through the door.
2. Description of Related Art
Delayed egress exit devices include a push rail or pad “request to exit” monitoring feature and are commonly used in schools, nursing homes, maternity wards, Alzheimer patient areas, psychiatric facilities, airports, shopping centers, libraries and other locations to provide a means of monitoring egress to prevent unauthorized exit through a door. When a delayed egress exit device is armed and the push rail or pad is depressed off of the normal home position, a monitoring feature within the device detects this movement and sounds a warning horn or alarm from the rail to alert personnel that someone is attempting egress. The sounding of the horn or alarm may be delayed to wait for the rail to remain depressed for a predetermined amount of time, e.g., 1-5 seconds, to avoid nuisance alarms. Depressing the rail or pad also triggers a “delay egress” condition which initiates a timer for a set period of time. The exit device may then stay secure and locked, preventing opening of the door and egress, for a desired amount of delay time, e.g., 15, seconds or more, thereby allowing time for personnel to respond to determine an appropriate response to the pending violation. After the set period of time expires, the push rail is released and functions as a standard exit device, allowing the door latch to unlock and open for free and immediate egress by the individual through the door. After this set period of time, the irreversible alarm state is then maintained until it is reset by authorized personnel. The exit device may be reset and re-armed automatically from the alarm condition after a predetermined period of time, e.g., 30-60 seconds, or may be reset manually, either at the door or by a remote control of the device.
Such delayed egress exit devices may be used to control most standard types of door locks and latches, such as rim, surface vertical rod, concealed vertical rod and mortise exit devices. They are typically self-contained within a rail assembly, external magnetic lock outputs available for extra high security. A standard size key-operated cylinder in the rail assembly or a remotely-connected device may be used by authorized personnel to disarm the device and provide momentary or maintained egress with key, e.g. 5-40 seconds or more, bypassing the alarm. The key may also be used by authorized personnel to reset the device. If connected to a fire or other remote alarm, the delayed egress device may also be disarmed to permit immediate egress if such alarm is triggered. Delayed egress exit devices on a bank of multiple doors may be connected for gang release of the delayed egress function when any door in the bank goes into alarm or the bank is otherwise remotely released.
A spring or other mechanism holds the push rail or pad of the delayed egress exit device in what is known as the extended or “home” position before and after it is depressed. If the push rail or pad of the device does not remain in or return to the proper home position when released, even if only by a minor distance, the product goes into “error mode” alerting the end user that the product is no longer operational. Failure of the rail or pad of the device to remain in or return to the proper home position may be caused by, mis-installation, tampering, blocking or worn-out components, and any other conditions that would influence the push rail or pad.